1. Technical Field
The present disclosure relates to a vehicle lamp. More particularly, the present disclosure relates to a vehicle lamp including a control unit that controls the lighting-up of a semiconductor light source including semiconductor light emitting elements and the drive of a cooling fan for suppressing the heat generation of the semiconductor light source.
2. Related Art
An illuminating device is known that includes light emitting diodes (LEDs), used as a semiconductor light source, and a cooling fan. The cooling fan is configured to prevent a high temperature condition of the LEDs caused by heat generated from the LEDs. The illuminating device is provided with a cooling fan drive circuit that controls the rotational drive of the cooling fan, and an LED drive circuit the controls the drive of the LEDs.
In this case, the cooling fan is provided on the back side of multiple LEDs and includes a rotatable propeller. Wind generated by the rotational drive of the propeller of the cooling fan is directed toward the LEDs, so that high temperature condition of the LEDs is prevented (see, e.g., JP-A-2001-216803).
In the related art, the fan drive circuit and the LED drive circuit are separately provided. For this reason, if the LEDs are cooled by the cooling fan, the cooling fan continues to be driven not only when the LEDs are turned ON, but also when the LEDs are turned OFF.
However, when the LEDs are turned OFF, the LEDs do not generate heat, and the cooling fan does not need to be driven. Accordingly, in the related art configuration, a problem arises because electric power is consumed unnecessarily. That is, in terms of electric power savings, it is advantageous that the cooling fan be driven only when the LEDs are turned ON, and the cooling fan be not driven when the LEDs are turned OFF. In the related art, the cooling fan is driven even when the LEDs are turned OFF. For this reason, it is not possible to achieve electric power savings and, thus, the life of the cooling fan is shortened.
Further, if current supply wiring to the cooling fan is opened, current is supplied only to the LEDs. Therefore, the LEDs continue to generate heat. In this case, the supply of current to the LEDs needs to be stopped in order to improve the durability of the LEDs. However, even though the cooling fan is not driven, the LEDs continue to generate heat in the related art configuration. For this reason, the life of the LED is shortened.
To solve the above-mentioned problem, components for monitoring the drive state of the cooling fan and the turning-ON state of the LEDs and components for controlling the cooling fan and the LEDs in accordance with the monitoring results are separately required. However, in such a case, as the number of parts is increased, it is difficult to reduce the manufacturing cost of the vehicle lamp.